The present invention relates to the manufacture of polyolefin resins. More particularly, it relates to the extrusion of polyethylene resins containing abherent additives such as an organic amide and a zinc salt.
An abherent additive is a substance that prevents or reduces adhesion of a material to itself or to another material. Other terms used for abherent additives include release agent, parting agent, antiblocking agent, slip aid, and external lubricant. Waxy amides are used as adherents in addition to their use as internal lubricants. The most common examples are ethylene bis(stearamide), oleamides, and erucamide. The metal salts of stearic acid, such as zinc stearate, and of other fatty acids are also widely used as abherents or release agents for polyolefins.